1. Field of the Invention
The present invention relates to a volume control apparatus in which a volume value is controlled by a controller.
2. Description of the Related Art
AV amplifier is connected to PC via network such as LAN, and contents reproduction is controlled by control program (hereinafter, controllers) installed into the PC. Server program (hereinafter, servers) is also installed into the PC, and a plurality of audio files are recorded in HDD of the PC. When audio file recorded in the HDD is selected by users' operation, the controller transmits instruction for reproducing the selected audio files to the AV amplifier. The AV amplifier requests the server to transmit the selected audio files. The server reads the selected audio files from the HDD and transmits them to the AV amplifier. The AV amplifier decodes the audio files transmitted from the server, and amplifies them so as to output sounds through speaker.
When instruction for changing controller-side volume setting value is input by users' mouse operation, controller transmits the changed controller-side volume setting value to AV amplifier. Accordingly, the AV amplifier controls the volume value at the time when the AV amplifier amplifies sound signals. Slide bar for changing the controller-side volume setting value by means of users' operation is provided to operation screens of the controller. When the slide bar is moved, the controller-side volume setting value is changed so that the volume value of the AV amplifier is controlled. Therefore, it is demanded that the volume values of the AV amplifier is suitably (namely, clearly for the users) changed according to the changes in the controller-side volume setting value.
When the user increases the controller-side volume setting value to maximum value (or around the maximum values) at a stroke, the volume value of the AV amplifier rises straight to the maximum value (or around the maximum values). As a result, amplifying circuit and speaker of the AV amplifier might be damaged.
Further, when a function for posting the volume value of the AV amplifier from the AV amplifier to the controller and changing the controller-side volume setting value according to the volume value of the AV amplifier are not provided, the following problem arises. When the controller is connected to the AV amplifier via LAN, the volume of the AV amplifier already has fairly large value (or the volume value of the AV amplifier is increased by operating volume control knob of not the controller but the AV amplifier), whereas the controller-side volume setting value is intermediate values, for example, (50 in the case of 0 to 100). In this case, when user views display of the controller-side volume setting value, falsely recognizes that the volume value of the AV amplifiers is still small, and thus increases the controller-side volume setting value, the volumes value of the AV amplifier becomes very large, and thus the AV amplifier and the speaker are damaged.